Missing Filmic Looks in Blender 2.81
You can replace the ocio configuration from blender, and use the one used by the author of Filmic Blender directly 

https://sobotka.github.io/filmic-blender/



Alternatively, to use the Greyscale look, you can manually edit the config.ocio file in the colormanagement folder and add the following stanza in the looks section:

looks:
  - !&lt;Look&gt;
    name: Greyscale
    process_space: Filmic Log Encoding
    transform: !&lt;MatrixTransform&gt; {matrix: [0.2126729, 0.7151521, 0.0721750, 0, 0.2126729, 0.7151521, 0.0721750, 0, 0.2126729, 0.7151521, 0.0721750, 0, 0, 0, 0, 1]}